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A prerequisite to soil management, particularly in degraded soils, is a good knowledge of the characteristics and fertility status of degraded soil, which is fundamental to planning suitable soil management strategies for crop production purposes. The aim of this study was to determine the physico-chemical and mineralogical properties and fertility constraints of degraded soils in Luzon, Philippines. Ten surface soil samples were collected from 10 degraded soils representing the dominant soil series in Luzon Island. These soils were analyzed for physical, chemical and mineralogical properties. Results revealed that all soils have high clay content (except Bantay soil), which impedes cultivation. All soils were acidic, have a very low organic matter (OM), total N, available P, and low to moderately low exchangeable cations. X-ray diffraction reveals the dominance of halloysite/kaolinite, quartz and hematite in all soils. Results further revealed that all soils have fertility constraints, particularly acidic soils, low OM, low total N, and low available P. All soils contain sufficient exchangeable Ca, but low to high exchangeable K, particularly in soils of Annam, Bolinao, Bantay and Cervantes. Together, these results suggest that all soils possess physical and chemical constraints to crop production and the occurrence of constraints varies with soil type, location in the landscape, slope and parent material. The recognition of these fertility constraints is essential for the long-term planning of soil management strategies essential to sustainable utilization of these degraded soils.